Funding for this research was provided by:
Peking University Health Science Center (BMU20160514)
National Natural Science Foundation of China (71803107)
Received: 14 June 2019
Accepted: 4 March 2020
First Online: 13 March 2020
Ethics approval and consent to participate
: The protocol for this study was approved in full by Institutional Review Boards at Stanford University (Palo Alto, California, USA) and the Zhongshan Ophthalmic Center of Sun Yat-sen University (ZOC, Guangzhou, China). Permission was received from local Boards of Education in each region and from the principals of all schools. The principles of the Declaration of Helsinki were followed throughout. The original trial (Registration site: ExternalRef removed. Registration number: ISRCTN03252665) was designed to study the effect of providing free spectacles on children’s educational performance.
: Not applicable.
: Prof Congdon declares that he works as Director of Research, a non-governmental organization active in delivery of children’s school-based refractive services in China.